The present invention relates to a method for mounting an LSI (large scale integrated circuit) on a wiring circuit substrate by hot pressing.
The conventional method for mounting an LSI chip on a wiring circuit substrate such as a film circuit substrate or printed circuit substrate, as shown in FIG. 5, comprises the step of placing the pins of the LSI chip "b" on the wiring circuit substrate "a" with a circuit pattern formed thereon, the step of covering the pins with a film sheet "d" coated with heat sealant "c", and the step of hotpressing the film sheet "d". Another conventional method is to bond the pins of the LSI chip "b" onto the wiring circuit substrate "a" with resin "e", as shown in FIG. 6.
The former method has the following defects: when hot-pressed, the heat sealant "c" on the film sheet "d" flows in the joint between the LSI chip "b" and the circuit pattern on the substrate "a", possibly impairing the insulation property. Besides, this method incurrs high material cost because it uses the film sheet "d" coated with heat sealant "c". The latter method is also defective in that it takes a long time for the resin "e" to cure and for the resin covers wide range of area, hampering high density mounting.